This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Surgical removal of brain tumors is the most common initial treatment received by brain tumor patients. Surgical resection can benefit the patients in several ways: for example, it relieves the mass effect of tumor on neurological tissue and allows histological diagnosis of the tumor, which directly affects the direction of follow-up therapeutic strategy (3). Many studies have demonstrated that aggressive surgical resection enhances the survival length and quality of life for brain tumor patients. Therefore, the goal of brain tumor resection procedures is to maximize tumor removal with minimal neurological damage. To achieve this goal accurate intraoperative identification of brain tumor margins during craniotomy is required. This study aims at the development of a means for visualizing brain tumor margins using optical techniques such as Modulated Imaging.